is your cycle length always the same or is it based off the length of your luteal phase? I always thought I was a 28 day cycle, but due to ovulating a day or two later (cycle day 16) my period is extended. My luteal phase is 12 days and that appears to be the only thing I can count on during my cycle.... so do you base your period on cycle length or days in your luteal phase? And by cycle length I mean a 28-30 day cycle? Today I’m 13dpo it was confirmed by OPK, ultrasound and on cycle day 24 I had a progesterone blood test that showed 22.7 was my level. I’m on cycle day 30 today. My period always starts 12dpo, but last month that fell on cycle day 30... I’m just confused on when I’m actually late for my period. One app tells me yesterday and another says today. I did clomid cycle day 3-7.